Concrete block machine with pallet locking dogs



Se t. 29, 1970 D. E. WHITEHURST 3,530,554

CONCRETE BLOCK MACHINE WITH PALLET LOCKING DOGS Filed March 25, 1968 2 Sheets-Sheet 1 H mm W H 5,... VI N H I W h BY ATTORNEYS p 1970 0. E. WHITEHURST I 3,530,554

CONCRETE BLOCK MACHINE WITH PALLET LOCKING DOGS Filed March 25, 1968 2 Sheets-Sheet 2 A I. 1m ,5 lg w INVENTOR. DONALD E. WHITEHURST ATTORNEYS United States Patent 3,530,554 CONCRETE BLOCK MACHINE WITH PALLET LOCKING DOGS Donald E. Wlaitehurst, Phoenix, Ariz., assiguor to Superlite Builders Supply, Inc., a corporation of Arizona Filed Mar. 25, 1968, Ser. No. 715,873 Int. Cl. B28]: 3/00 US. C]. 25-41 8 Claims ABSTRACT OF THE DISCLOSURE A pair of shafts are rotatably mounted adjacent a lower edge of the molds in a concrete block machme. A plurality of locking dogs are mounted on the shaft and, to-

gether with the shaft, are positionable between an un- The present invention relates to concrete block making machines and, more specifically, to a concrete block machine having modifications therein to improve the capacity of the machine to manufacture slump block.

The state of the art of concrete block machines is fairly well developed and includes numerous patents relating to the mechanical, electrical, pneumatic, and hydraulic functions of complicated machinery for the automatic manufacture of concrete blocks. characteristically, these machines utilize a plurality of stationary molds having open tops and bottoms; a pallet is placed in the bottom of the mold and concrete is fed into the top of the molds to form concrete blocks. The pallets are subsequently lowered to remove any newly formed concrete blocks from the molds which are then transferred on the pallet to a storage location for curing. The specific compositions utilized in making concrete block may vary; however, one type of concrete block presently being manufactured has given rise to unique problems in the automatic manufacture thereof. This type of block, called slump block, utilizes a concrete mixture considerably more fluid than the more conventional blocks. This less viscous nature of the raw concrete has resulted in the problem of feathering caused "by slight leakage occurring between the bottom of the mold and the pallet during the forming of the block. Further, since concrete block machines characteristically use vibration as a technique for settling the concrete in the molds, the tendency for leakage is increased.

The concrete blocks thus manufactured have feathering or rough edges which must subsequently be removed before use.

It is therefore an object of the present invention to provide an improvement for concrete block making machines that will enable such machines to manufacture slump blocks without feathering.

It is another object of the present invention to provide a slump block machine that will automatically provide a locking means for firmly clamping the pallet into contact with the mold to prevent leakage which results from the utilization of less viscous raw concrete mixtures.

These and other advantages of the present invention will become apparent tothose skilled in the art as the description thereof proceeds.

Briefly, in accordance with the embodiment chosen for illustration, a pair of shafts are positioned along opposite lower edges of the concrete block molds in a concrete block machine. The shafts are rotatably mounted and have locking dogs secured thereto. Each shaft terminates in a sprocket keyed thereto to permit torque to be transmitted to the shaft. A pair of pneumatic cylinders are positioned in alignment with the sprocket and a flexible chain is mounted over the sprocket and secured at either end thereto to the operating arms of the pneumatic pistons. The pneumatic pistons are selectively actuated, thus causing the shaft to rotate and rotate the dogs into locking engagement with the pallet.

The present invention may more readily be described by reference to the accompanying drawings, in which:

FIGS. 1a1d are schematic representations of the system of the present invention showing progressive steps in the operation thereof.

FIG. 2 is an enlarged bottom view of a portion of the system of FIG. 1 showing a pallet being held in firm engagement with the bottom of the molds by the locking dogs.

FIG. 3 is a perspective View of a portion of FIG. 1 showing a rotatable shaft with the locking dogs secured thereto and showing the pneumatic cylinders connected to the shaft through a flexible chain arrangement.

Referring now to the drawings, the block machine upon which the present invention is utilized is only shown schematically; those skilled in the art will readily recognize the environment of the present invention when mounted on a block making machine. A mold 10 is fed through the open top 11 thereof through a chute (not shown). A measured amount of raw concrete descends into the mold 10 which is vibrated to insure compaction of the concrete. A pair of shafts, such as the shaft 12, extends along one bottom edge of the mold 10 and is journalled for rotation by any suitable means to the frame of the block making machine, such as the portion of the frame 13 shown in FIG. 1. The shaft 12 includes locking dogs 14 and 15 secured thereto. One end 20 of the shaft 12 is keyed to a sprocket 22 (FIG. 3) to provide a coupling means for transmitting torque to the shaft. A pair of pneumatic cylinders 25 and 26 are mounted above the sprocket 22 and include operating arms 27 and 28 respectively extending downwardly therefrom. A flexible chain 30 is connected to each of the operating arms 27 and 28 and passes over in contact With the sprocket 22.

An electrical switch having an operating button 36 is positioned so that the button extends into the path of any pallet coming into contact with the lower edge 37 of the mold 10. The electrical signal derived through the actuation of the switch is provided toa valve actuator 38. A pneumatic pressure source 40 provides high pressure air through a conduit 41 to a bi-directional valve 42 operating under the control of the valve actuator 38. The valve 42 thus applies the pressure provided from the pressure source 40- to either conduit 45 or conduit 46, While automatically venting that conduit which it does not connect to the high pressure source. The concrete block making machine includes a control system which controls the many functions and overall sequence of the system. Such a control actuator is shown schematically at 50. The control actuator will receive position signals from the various components of the machine and provide control signals in response thereto.

A pallet feed conveyor receives empty pallets and transmits them to a pallet elevator 56 which is utilized to lift the pallet into position beneath the mold 10. A pallet such as 57 usually comprises a flat metal plate that receives the uncured concrete block and is usually used to store the block during curing. A loaded pallet feed platform 59' is positioned for horizontal movement between a ready position and a feeding position to receive loaded pallets and transfer the pallets to a loaded pallet conveyor 60.

The operation of the improvement of the present invention may now be described. A pallet such as the pallet 57 is fed by the conveyor 55 into the pallet elevator 56 (FIG. la). The pallet elevator lifts the pallet into contact with the lower edge of the mold (FIG. lb). As the pallet approaches the bottom edge of the mold, the pallet contacts the switch button 36 to thereby derive a locking signal to indicate to the valve actuator 38 that the pallet is now in position. The valve actuator directs high pressure air to the conduit 45, thus causing the actuating arm 28 to be withdrawn into the cylinder 26. The conduit 46 is simultaneously vented to the atmosphere, thereby permitting the pneumatic pressure to force the actuating arm 28 into the cylinder 26. This force is transmitted to the flexible chain 30 to the sprocket 22 to provide torque to the shaft 12. The shaft thus rotates, causing the dogs 14 and to clamp the pallet 57 into firm and locked contact with the bottom of the mold. Simultaneously, the loaded pallet feed platform 59 moves to the left (as shown in FIG. 1) to a position beneath the pallet. When the mold loading operation has been terminated as determined by the control actuator 50 of the block machine, the valve actuator reverses the valve 42, thereby reversing the direction of torque applied to the shaft 12. The pallet is thus unlocked and the pallet with the uncured blocks thereon are lowered by the pallet elevator. The lowering motion of the loaded pallet (now supporting uncured concrete blocks such as the block 65) is interrupted by the loaded pallet feed platform 59. The pallet elevator 56 is formed by a pair of parallel plates, the size of which are shown in FIG. 1, which, in their downward movement with the loaded pallet, straddle the loaded pallet feed platform 59, thereby transferring the loaded pallet to the loaded pallet feed platform (FIG. 10).

The loaded pallet feed platform 59 continues its leftward motion to transfer the loaded pallet to the conveyor 60. The uncured block supported on its pallet is conveyed from the machine while the loaded pallet feed platform 59 returns to its starting position and the pallet elevator 56 begins its upward motion with a new pallet.

In the embodiment chosen for illustration, pneumatic cylinder were shown; however, it will be obvious to those skilled in the art that solenoids could be substituted therefor. Further, the specific arrangement may substantially be varied to provide the desired force at the dogs to insure clamping action. To this end, the length of travel of the operating arms of any pneumatic cylinders or solenoids together with the diameter of the sprocket or other equivalent coupling means may be chosen to provide the desired torque for the shaft 12. It has been found that two shafts, each having a pair of dogs secured thereto, is adequate to prevent feathering; it may be necessary, however, to increase the number of dogs in the event it is found that other parameters require a more even application of clamping force (such as the utilization of pallets that are not sufficiently rigid). It may therefore be seen that the present invention may be modified from the specific embodiment chosen for illustration without departing from the spirit and scope thereof. It is therefore intended that the present invention be limited only by the scope of the claims appended hereto.

I claim:

1. In a concrete block making machine having a plurality of topless and bottomless molds for receiving fresh concrete through the top thereof, a pallet elevator for receiving pallets from a pallet conveyor and lifting said pallets to a position beneath said molds to receive newly formed concrete blocks, the improvement comprising: means responsive to the positioning of said pallets beneath said moles for generating a locking signal; a pair of oppositely disposed shafts rotatably mounted adjacent a bottom edge of said molds and each having a plurality of locking dogs secured thereto, each said shaft and dogs rotatable between an unlocked position to permit positioning of said pallets beneath said mold and a locked position to forcibly hold said pallets into engagement with the bottom of said molds; coupling means secured to each said shaft for transmitting torque thereto; torque means responsive to said locking signal for applying a locking torque to each said shaft through said coupling means, and responsive to the absence of said locking signal upon completion of a mold loading operation for applying an unlocked torque to each said shaft through said coupling means.

2. The combination set forth in claim 1 wherein said torque means includes a pair of cylinders, each having an operating rod extending axially therefrom and axially positionable to a locking and an unlocking position, and including means connecting said operating rods to said coupling means.

3. The combination set forth in claim 2 wherein said means connecting said operating rods is a flexible member.

4. The combination set forth in claim 2 wherein said cylinders and operating rods are pneumatically actuated.

5. The combination set forth in claim 2 wherein said cylinders and operating rods are electrically actuated.

6. The combination set forth in claim 2 wherein said means connecting said operating rods is a flexible chain and wherein said coupling means comprises a sprocket engaging said flexible chain.

7. The combination set forth in claim 6 wherein said cylinders and operating rods are pneumatically actuated.

8. The combination set forth in claim 6 wherein said cylinders and operating rods are electrically actuated.

References Cited UNITED STATES PATENTS 2,496,016 1/1950 Nelson 2542 2,713,184 7/1955 Galabedian 164-341 3,435,884 4/1969 Orris et al 1-6434l FOREIGN PATENTS 1,115,033 12/1955 France.

ROBERT D. BALDWIN, Primary Examiner U.S. Cl. X.R. 7489.2l 

